Hybrid Pharmacologic and Ablative Therapy: A Novel and Effective Approach for the Management of Atrial Fibrillation

Hybrid Therapy for Atrial Fibrillation. Introduction: Maintenance of sinus rhythm in patients with recurrent atrial fibrillation is often difficult to achieve with pharmacologic therapy. Complex catheter ablative procedures are being developed, but efficacy and safety issues remain to be clarified. We hypothesized that combined pharmacologic and simple ablative therapies in a targeted subset of patients will improve success in the treatment of atrial fibrillation. Methods and Results: We identified 13 patients (mean age 61.5 ± 16.2 years) with atrial fibrillation who converted to electrocardiographic atrial flutter during antiarrhythmic drug treatment. Surface ECG suggested “typical” atrial flutter in 11 patients and “atypical” atrial flutter in 2. Intracardiac mapping and entrainment studies revealed 9 patients had counter-clockwise isthmus-dependent atrial flutter, and the remaining 4 had complex activation patterns, suggesting the presence of multiple wavefronts. All 9 patients with typical atrial flutter underwent successful ablation. None of the 4 patients with complex activation patterns had successful ablation. Patients were followed for recurrences of atrial arrhythmias via clinic visits, record review, and interviews. In patients who underwent successful ablation and continued on antiarrhythmic drugs, 88.9% remain in sinus rhythm after a mean follow-up of 14.3 ± 6.9 months (range 1 to 28). Conclusion: In patients who experience conversion of atrial fibrillation to atrial flutter during antiarrhythmic drug treatment, ablation and continuation of pharmacologic therapy is a safe and effective means of achieving and maintaining sinus rhythm.     

Amiodarone in Atrial Fibrillation

ABSTRACT Twenty-seven patients with atrial fibrillation without any concomitant conduction abnormality have been treated with oral amiodarone in a daily maintenance dose of 200 mg. The drug has been used for three purposes: 1) to block atrioventricular conduction, thereby decreasing the ventricular rate during atrial fibrillation (9 patients), 2) as prophylaxis against paroxysmal atrial fibrillation (8 patients), 3) as prophylaxis against recurrence of atrial fibrillation after DC conversion to sinus rhythm (13 patients). All patients were considered refractory to other antiarrhythmic drugs in these respects. In the second group, 4 of the 8 patients reported complete cessation of attacks and the others a marked reduction of the attack rate. In the third group, 10 of the 13 patients have maintained sinus rhythm for a longer period on treatment with amiodarone than with other drugs, resulting more than a triple prolongation of the time in sinus rhythm. In 3 patients the drug has been discontinued because of side-effects. In conclusion, amiodarone affords protection from episodes of paroxysmal atrial fibrillation, as well as from recurrence of atrial fibrillation after DC conversion to sinus rhythm. If the drug is ineffective in either of these respects, it may still be useful as a means of moderating the ventricular response in atrial fibrillation.     

Efficacy of intravenous amiodarone in the management of paroxysmal or new atrial fibrillation with fast ventricular response

We tested the efficacy of intravenous amiodarone (5 mg/kg) in slowing ventricular response and/or restoring sinus rhythm in 26 patients with paroxysmal or new atrial fibrillation with fast ventricular response. There were 16 men and 10 women with ages ranging from 35 to 84 years, mean 63 years. Intravenous amiodarone initially slowed the ventricular response in all patients from 143 +/- 27 to 96 +/- 10 beats/min (P less than 0.001). Twelve patients (46%) reverted to sinus rhythm within the first 30 min (range 5 to 30 min, mean 14 +/- 9 min). One patient reverted to atrial flutter after 10 min and 40 min later to sinus rhythm. Six patients (23%) converted to sinus rhythm after 2 to 8 hr and in these 6 cases, the initial slowing in ventricular response obtained with amiodarone persisted until conversion. Seven patients (27%) did not convert to sinus rhythm following amiodarone administration and they required further medical therapy to slow the ventricular response and/or to convert to sinus rhythm. No serious side effects from drug administration were noted. Intravenous amiodarone appears as a highly effective medication in the conversion or control of new onset atrial fibrillation with fast ventricular response.     

A Review of Clinical Trials Assessing the Efficacy and Safety of Newer Antiarrhythmic Drugs in Atrial Fibrillation

Clinical trials assessing the efficacy of anti- arrhythmic drugs for terminating atrial fibrillation have demonstrated that rate control drugs have little to no added efficacy compared to placebo; however, spontaneous conversion of recent-onset atrial fibrillation is common. Antiarrhythmic drugs such as oral dofetilide, oral bolus-flecainide and propafenone and intravenous ibutilide all have a role in terminating atrial fibrillation. Active comparator trials have demonstrated that amiodarone is more efficacious in maintaining sinus rhythm than propafenone and sotalol. Multiple trials have demonstrated the safety of amiodarone, sotalol, dofetilide and azimilide in a post-myocardial infarction population and amiodarone and dofetilide in a congestive heart failure population. Newer antiarrhythmic agents, some with novel mechanisms of action, will add to the pharmacologic armamentarium in treating atrial fibrillation.     

Role of transthoracic echocardiography in atrial fibrillation

Atrial fibrillation is a major clinical problem that is predicted to be encountered more frequently as the population ages. The clinical management of atrial fibrillation has become increasingly complex as new therapies and strategies have become available for ventricular rate control, conversion to sinus rhythm, maintenance of sinus rhythm, and prevention of thromboembolism. Clinical and transthoracic echocardiographic features are important in determining etiology and directing therapy for atrial fibrillation. Left atrial size, left ventricular wall thickness, and left ventricular function have independent predictive value for determining the risk of developing atrial fibrillation. Left atrial size may have predictive value in determining the success of cardioversion and maintaining sinus rhythm in selected clinical settings but has less value in the most frequently encountered group, patients with nonvalvular atrial fibrillation, in whom the duration of atrial fibrillation is the most important feature. When selecting pharmacological agents to control ventricular rate, convert to sinus rhythm, and maintain normal sinus rhythm, transthoracic echocardiography (TTE) allows noninvasive evaluation of left ventricular function and hence guides management. The combination of clinical and transthoracic echocardiographic features also allows risk stratification for thromboembolism and hemorrhagic complications in atrial fibrillation. High-risk clinical features for thromboembolism supported by epidemiological observations, results of randomized clinical trials, and meta-analyses include rheumatic valvular heart disease, prior thromboembolism, congestive heart failure, hypertension, older (> 75 years old) women, and diabetes. Small series of cases also suggest those with hyperthyroidism and hypertrophic cardiomyopathy are at high risk. TTE plays a unique role in confirming or discovering high-risk features such as rheumatic valvular disease, hypertrophic cardiomyopathy, and decreased left ventricular function. Validation of the risk stratification scheme used in the Stroke Prevention in Atrial Fibrillation-III trial is welcomed by clinicians who are faced daily with balancing the benefit and risks of anticoagulation to prevent thromboembolism in patients with atrial fibrillation.     

Catheter ablation of atrial fibrillation in heart failure with reduced ejection fraction

Atrial fibrillation and heart failure are increasing in prevalence, and frequently coexist. Despite the desire to restore sinus rhythm in heart failure patients, large studies comparing rate control to pharmacologic rhythm control have failed to show superiority of either approach. This may in part be due to the inefficacy and higher risk of adverse effects with antiarrhythmic drugs in HF patients. As such, catheter ablation for atrial fibrillation in patients with heart failure with reduced ejection fraction has been increasingly explored as a treatment modality. We review the contemporary evidence regarding patient selection, efficacy, safety, and impact of catheter ablation on outcomes in patients with atrial fibrillation and heart failure with reduced ejection fraction.     

Pharmacotherapy of Atrial Fibrillation

Atrial fibrillation is a common medical problem that has a wide clinical spectrum ranging from a benign condition, such as “lone” atrial fibrillation, to a life-threatening arrhythmia, when there is an accessory pathway. There is a striking contrast between the frequency of atrial fibrillation and the absence of well-defined, scientifically based medical management. At least four considerations guide the pharmacological treatment of patients with atrial fibrillation: (1) restoration of sinus rhythm; (2) acute and long-term control of the ventricular rate; (3) maintenance of sinus rhythm; and (4) anticoagulation. Pharmacological cardioversion is best achieved with intravenous flecainide, intravenous propafenone, or intravenous ibutilide. During episodes of atrial fibrillation, the drugs of first choice for control of the ventricular rate are calcium antagonists and beta-blockers. Digitalis is helpful in elderly patients and in cases with congestive heart failure. Maintenance of sinus rhythm is a complex task, owing to the proarrhythmic potential of antiarrhythmic drugs, and the treatment should be tailored to the individual patient's needs. No one drug is clearly better than another. As for amiodarone, its benefit/risk ratio remains to be evaluated prospectively. Usually, most of the patients benefit from serial electrical cardioversion, with the longest possible interval between cardioversion sessions being sought. The question about whether the aim of the treatment of atrial fibrillation should be to control the ventricular rate or to restore sinus rhythm will be answered by ongoing trials. The effectiveness of low-dose anticoagulation in preventing stroke in patients with nonrheumatic atrial fibrillation has been validated by seven separate studies. Anticoagulation with warfarin should be monitored carefully in order to achieve an International Normalized Ratio (INR) of between 2.0 and 3.0. This targeted INR decreases the embolic rate and eliminates the risk of intracranial bleeding. The role of aspirin alone in decreasing the risk of stroke remains to be established. Pharmacological management of patients with atrial fibrillation has to be improved, by better risk stratification and the development of new drugs with an optimal benefit/risk ratio. Ongoing trials are expected to provide important guidelines, corresponding to the needs of the many different types of patients with atrial fibrillation.     

Atrial Fibrillation in Heart Failure:

Atrial fibrillation and congestive heart failure are commonly occurring cardiac disorders that often exist concomitantly. The prognostic significance of the presence or absence of atrial fibrillation, as an independent risk factor, in patients with heart failure remains controversial. Antiarrhythmic drugs with good hemodynamic profiles and neutral effects on survival are preferred treatments for converting atrial fibrillation and maintaining sinus rhythm. Other standard therapies for congestive heart failure, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and beta-blockers also have a role in the treatment of these coexisting disease states. The article presents an overview of atrial fibrillation in patients with heart failure and reviews the prevalence, prognostic significance, and efficacy of various antiarrhythmic agents for the conversion and maintenance of sinus rhythm. (J Cardiovasc Electrophysiol, Vol. 14, pp. S281-S286, December 2003, Suppl.)     

The effect of magnesium versus verapamil on supraventricular arrhythmias

Magnesium has previously been used in the treatment of various arrhythmias, but few randomized and prospective studies are available. In a single-blind study, the efficacy and safety of intravenous magnesium sulfate (bolus doses of 5 + 5 mmol followed by infusion of 0.04 mmol/min) versus verapamil (5 + 5 mg followed by 0.1 mg/min) was evaluated in 57 patients with supraventricular arrhythmias (supraventricular tachycardia, atrial fibrillation, and atrial flutter) of recent onset (less than 1 week). Fifteen (58%) of the patients receiving magnesium (n = 26) converted to sinus rhythm within 4 h, and 16 (62%) within 24 h. Verapamil caused a lower ventricular rate, but only six (19%) of the patients (n = 31) converted to sinus rhythm within 4 h (p < 0.01) and 16 (52%) within 24 h (NS). No side effects were observed during magnesium infusion, whereas six patients receiving verapamil had to be withdrawn from further study medication due to symptomatic side effects (hypotension in three, cardiac failure in three). Magnesium appears to be an effective and safe drug for the treatment of supraventricular arrhythmias. The overall efficacy for conversion to sinus rhythm is at least as effective as with verapamil, and its action is more rapid.     

缬沙坦氢氯噻嗪片治疗阵发性心房纤颤的疗效观察

目的探讨缬沙坦氢氯噻嗪片治疗阵发性心房纤颤的临床疗效。方法将118例阵发性心房纤颤患者随机分成2组,对照组59例给予常规药物胺碘酮进行治疗,治疗组59例则给予缬沙坦氢氯噻嗪片治疗,比较2组的疗效和安全性,随访1年。结果 2组在治疗后3月的窦性心律维持率无显著性差异,治疗后6、12月治疗组的窦性心律维持率均明显高于对照组(P<0.05)。治疗后6月,2组患者的左心房内径无显著性差异,但治疗后12月,治疗组的左心房内径明显小于对照组(P<0.05)。结论缬沙坦氢氯噻嗪片治疗阵发性心房纤颤的临床疗效显著,其临床用药既有效又安全。     

Persistent Atrial Flutter in Patients Treated for Atrial Fibrillation with Amiodarone and Propafenone:

INTRODUCTION: Antiarrhythmic drugs have been reported to promote the conversion of atrial fibrillation to atrial flutter in patients with paroxysmal atrial fibrillation. However, information about the electrophysiologic mechanism and response to radiofrequency ablation of these drug-induced atrial flutters is limited. Furthermore, the determinants of the development of persistent atrial flutter in patients treated for atrial fibrillation with antiarrhythmic drugs are still unknown. METHODS AND RESULTS: Among the 136 patients treated for atrial fibrillation with amiodarone (n = 96) or propafenone (n = 40), 15 (11%, mean age 65.5 +/- 12.3 years) were identified to have subsequent development of persistent atrial flutter based on surface ECG characteristics during antiarrhythmic drug treatment. The mean interval between the beginning of drug treatment and the onset of atrial flutter was 5.0 +/- 5.5 months. Intracardiac mapping and entrainment studies revealed that 11 patients had counterclockwise typical atrial flutter, and 4 had clockwise typical atrial flutter. All 15 patients underwent successful ablation with creation of complete bidirectional isthmus conduction block. After a mean follow-up of 12.3 +/- 4.2 months, 14 (93%) of 15 patients who underwent successful ablation and continued taking antiarrhythmic drugs have remained in sinus rhythm. Univariate analysis of clinical variables demonstrated that only atrial enlargement was significantly related to the occurrence of persistent atrial flutter. CONCLUSION: In patients with atrial fibrillation, persistent typical atrial flutter might occur during antiarrhythmic drug treatment, and atrial enlargement was a risk factor for the development of such an arrhythmia. Radiofrequency ablation and continuation of pharmacologic therapy offered a safe and effective means of achieving and maintaining sinus rhythm.     

The pharmacologic treatment of atrial fibrillation

The pharmacologic treatment of atrial fibrillation (AF) is aimed at controlling the ventricular response, restoring sinus rhythm, and preventing or delaying relapses. In the control of ventricular response, digitalis maintains a primary role when the arrhythmia is accompanied by heart failure. In ischemic, hypertensive, and degenerative (whose number is increasing at present) cardiopathies without evident ventricular dilatation, treatments with calcium antagonists (such as verapamil, gallopamil, or diltiazem) or beta-blocking agents must be preferred. In order to control the ventricular response in patients with chronic AF during physical activity, the association of digitalis with beta-blocking agents or calcium antagonists seems to provide satisfactory results. The drugs of the IC class, especially flecainide, represent a certain therapeutical progress in the restoration of sinus rhythm in the treatment of paroxysmal atrial fibrillation affecting subjects without evident alterations of ventricular function, particularly in subjects with Wolff-Parkinson-White syndrome, with forms of vagal origin, or with atrial fibrillation alone. A therapeutic combination of digitalis and quinidine may produce resolution of the arrhythmia in the presence of altered ventricular function or when AF is of an uncertain onset. In patients with hypertensive, ischemic, and/or degenerative cardiopathy without evident ventricular or advanced heart failure, the verapamil-quinidine association may also be effective and even quicker. The combination of drugs of the I and III class for restoration of the sinus rhythm in particularly resistant forms of AF without evident structural heart alterations is promising but must be verified in a greater number of patients. In the prevention of relapses amiodarone appears to have the widest spectrum of advantages from an electrophysiologic point of view; however, because of its many side effects, amiodarone represents a late therapeutical choice. The promising results obtained with flecainide are disputed by the results of the CAST, which limit the possibilities of using this drug to a low number of cases (W.P.W. syndrome, AF of vagal origin, atrial fibrillation alone). In the past, quinidine and disopyramide have been the drugs most widely used in the prophylaxis of AF. These drugs have a similar efficacy, and both of them provided some positive results. However, because of untoward side effects (especially for quinidine) during chronic treatment, the use of these drugs has been questioned. Perhaps in the majority of patients, the less dangerous therapeutic choice after the termination of the fibrillation is a combination of drugs slowly down AV node activity (digitalis or calcium antagonists and beta blockers) with class IA antiarrhythmics.     

Comparison of intravenously administered dofetilide versus amiodarone in the acute termination of atrial fibrillation and flutter. A multicentre, randomized, double-blind, placebo-controlled study.

AIMS: This study compared the efficacy and safety of intravenous dofetilide with amiodarone and placebo in converting atrial fibrillation or flutter to sinus rhythm. METHODS AND RESULTS: One hundred and fifty patients with atrial fibrillation or flutter (duration range 2 h-6 months) were given 15-min intravenous infusions of 8 microg. kg(-1)of dofetilide (n=48), 5 mg. kg(-1)of amiodarone (n=50), or placebo (n=52) and monitored continuously for 3 h. Sinus rhythm was restored in 35%, 4%, and 4% of patients, respectively (P<0.001, dofetilide vs placebo;P=ns, amiodarone versus placebo). Dofetilide was more effective in atrial flutter than in atrial fibrillation (cardioversion rates 75% and 22%, respectively;P=0.004). The mean time to conversion with dofetilide was 55+/-15 min. Dofetilide prolonged the QTc interval (+16% at 20 min). Amiodarone substantially decreased the ventricular rate in non-converters (-18 beats. min(-1)at 30 min). Two patients given dofetilide (4%) had non-sustained ventricular tachycardias, and four (8%) had torsade de pointes, in one case requiring electrical cardioversion. CONCLUSION: Intravenous dofetilide is significantly more effective than amiodarone or placebo in restoring sinus rhythm in patients with atrial fibrillation or flutter. However, when infused intravenously at this dose and rate, dofetilide causes a significant incidence of torsade de pointes.     

血压变异性与心房颤动相关性研究

［］ 目的 探讨血压变异性(BPV)对心房颤动发生及左心结构的影响。方法 随机选取我科2013年6月至2015年10月就诊患者120例患者,其中永久性房颤40例,持续性房颤40例,阵发性房颤40例,选取同期住院的窦性心律患者40例,测24h动态心电图、动态血压、超声心动图对160例患者检测,比较四组患者血压变异性及左房内径。 结果 心房颤动组的血压变异性、左房内径较正常对照组明显增加,房颤组内比较,永久性房颤组较持续性房颤组、阵发性房颤组血压变异性明显增大。 结论 心房颤动的患者血压变异性明显增加,且心房颤动的严重程度与血压变异性呈正相关。#$NL［关键词］心房颤动;血压变异性;左房内径     

Confounding Factors in Rate Versus Rhythm Control Trials in Patients with Atrial Fibrillation: Lessons from the Strategies of Treatment of Atrial Fibrillation (STAF) Pilot Study

Background: The Strategies of Treatment of Atrial Fibrillation (STAF) multicenter pilot trial was one of five completed clinical studies to compare two treatment strategies in patients with atrial fibrillation: the strategy of rhythm control (restoration and maintenance of sinus rhythm) and the strategy of rate control (pharmacologic or invasive rate control and anticoagulation). Methods: In STAF 200 patients (100 per group) with persistent atrial fibrillation were randomized to rhythm or rate control. The combined primary endpoint was a combination of death, cardiopulmonary resuscitation, cerebrovascular event, and systemic embolism. Results: After 19.6 ± 8.9 (0–36) months there was no difference in the primary endpoint between rhythm control (9/100; 5.54%/year) and rate control (10/100; 6.09%/year; p = 0.99). The percentage of patients in sinus rhythm in the rhythm control group after up to four cardioversions during the follow-up period was 23% at 36 months compared to 0% in the rate control group. Eighteen primary endpoints occurred in atrial fibrillation, only 1 occurred in sinus rhythm (p = 0.049). Conclusions: The STAF pilot trial did not show any differences between the two treatment strategies in common with other trials of rhythm versus rate control. These data suggest that there is no benefit in attempting rhythm control in this group of patients with a high risk of arrhythmia recurrence. It remains unclear whether the results in the group of rhythm control would have been better if sinus rhythm had been maintained in a higher proportion of patients since all but one endpoint occurred during atrial fibrillation.Atrial fibrillation; Electric Countershock; Anti-Arrhythmia Agents; Clinical trial, randomized clinical trial     

Atrial Fibrillation and Flutter: Maintaining Stability of Sinus Rhythm Versus Ventricular Rate Control

Atrial Fibrillation and Flutter. Two major treatment strategies have emerged for managing atrial fibrillation: maintaining sinus rhythm by chronic administration of suppressive antiarrhythmic agents versus controlling the ventricular rate and chronic anticoagulation. Potential benefits of maintenance of sinus rhythm include improvement of the hemodynamic profile of the patient, a decreased risk of cerebrovascular accidents, reduced symptoms, and, if atrial fibrillation is successfully suppressed, possible elimination of the need for chronic anticoagulation. When selecting long-term antiarrhythmic drug therapy for suppression of atrial fibrillation, it should he recalled that at least 50% of patients have a recurrence of the arrhythmia within the first year and the majority of other patients have a recurrence within the next 3 to 5 years. In addition, the risk of proarrhythmia and sudden cardiac death must be considered: this has stimulated interest in nonpharmacologic approaches to maintaining sinus rhythm. Large multicenter randomized trials are now under way to compare the benefits and risks of maintaining sinus rhythm versus controlling the ventricular rate and chronically anti-coagulating patients in atrial fibrillation. Important endpoints of these trials include mortality, functional capacity, and quality of life.     

阵发性心房颤动发作特点的研究

目的：分析阵发性心房颤动（房颤）的发作特点。方法：42例阵发性房颤患者分成有器质性心脏病和无可发现的器质性心脏病2例,共进行45次24h动态心电图检查,对比房颤发作前30min和1min的窦性心室率,以及诱发和不诱发房颤的房性早搏的配对间期（PP′）和早搏指数（PI）。结果：随机抽取53例次的阵发性房颤样本。房颤发作前30min和1min的平均窦性心室率改变不显著。但14例次（33％）和15例次（36％）房颤发作前1min的窦性心室率＜60次／min,与53个不诱发房颤的房性早搏相比。48个诱发房颤的房性早搏的PP′间期和PI均显著缩短（P＜0．001）。有器质性心脏病和无器质性心脏病的2组阵发性房颤患者的各项观察指标差异均显著性。结论：短配对间期的房性早搏是阵发性房颤的独立诱发因素,部分患者的房颤发作与心动过缓有关,采取相应的治疗措可能预防房颤的发生。     

替米沙坦联合胺碘酮维持阵发性心房颤动患者窦性心律的作用

目的 观察非瓣膜病阵发性心房颤动(房颤)的患者应用替米沙坦在房颤复律后维持窦性心律的疗效. 方法 76例非瓣膜病变阵发性房颤患者,随机分为胺碘酮对照组和替米沙坦+胺碘酮治疗组(联合治疗组),观察治疗后3、6、12个月两组患者左心房内径的变化及评价窦性心律的维持效果. 结果 治疗3、6个月两组左心房内径和窦性心律维持率差异无统计学意义(分别为t=0.04、0.51和t=0.03、1.12,均为P>0.05).治疗1年后,两组窦性心律的维持率分别为48.4%和73.5%,左心房内径分别为(37.26±4.85)mm和(34.38±3.85)mm,联合治疗组窦性心律维持率高于对照组(t=4.33,P<0.05),左房内径小于对照组(t=2.66,P<0.05). 结论 替米沙坦联合胺碘酮对阵发性房颤复律后窦性心律维持优于单用胺碘酮治疗,随着时间延长,维持窦性心律效果越好,可能与替米沙坦抑制肾素血管紧张素系统,降低心脏负荷,抑制心房电及结构重构有关.     

The Patient with Atrial Fibrillation

Atrial fibrillation is a frequently encountered arrhythmia, particularly affecting the elderly. Patients at significant risk for stroke should be considered for anticoagulation with warfarin. Management of atrial fibrillation revolves around either controlling the ventricular rate response or trying to maintain sinus rhythm with either pharmacologic or nonpharmacologic therapies. There are many treatment options to consider, based upon the patient's expectations, symptoms, and comorbid conditions. Therefore, the treatment of atrial fibrillation must be individualized.     

Should every patient with atrial fibrillation have the rhythm coverted to sinus rhythm?

Atrial Fibrillation is the most common atrial tachyarrhythmia. Consideration for the potential conversion of atrial fibrillation and the subsequent maintenance of sinus rhythm may be related to underlying pathology. Typically, extra cardiac factors such as thyroid hyperactivity help to determine initial therapy. Intrinsic cardiac factors may also influence the clinician's decision regarding potential cardioversion and maintenance of sinus rhythm. Some acute events such as pericarditis and the effects of cardiac trauma may resolve and result in spontaneous restoration of sinus rhythm. Other cardiac events such as acute myocardial infarction with with or without atrial ischemia, valvular disease, and others may result in the precipitation of atrial fibrillation. The major reasons to consider cardioversion, either medically or electrically, are ventricular rate control, hemodynamic improvement, sense of well being, and the avoidance of embolism. Certain clinical situations (e.g., Wolff-Parkinson-White syndrome) require urgent restoration of sinus rhythm in light of the potential for extremely rapid ventricular rates. It has been suggested that all antiarrhythmic drug administration should be initiated in the hospital setting, but the brief period of drug administration in an inpatient setting does not protect the patient from potential, late-onset proarrhythmic events. Both antiarrhythmic drug therapy and electric cardioversion are useful for restoration of sinus rhythm in both acute and chronic atrial fibrillation. The most important negative aspect of drug conversion of atrial fibrillation may be the potential development of a proarrthmic drug effect. Although controversial, conversion (medical or electrical) is probably indicated in every patient with the first episode of persistent atrial fibrillation, even if the patient is asymtomatic. The problem of recurrent atrial fibrillation requires clinical judgment relative to the frequency of episodes, the underlying disease(s) and the need for maintenance of a sinus mechanism.